I made a stylesheet and stored it in style library/themable/Core styles folder in root site beacuse I was not able to see the style library in the subsite.
I linked it in the master page before closing head tag
<link href="/Style Library/Themable/Core Styles left navigation pane.css" rel="stylesheet" type="text/css" />
I am still not able to change the background colour of the left navigation bar..
I have activated the publishing feature both at the site level as well as at the subsite level.
The master page where I made the changes was seattle and it is the default master page applied on the subsite. I confirmed this by going to site settings /master page.
Please suggest